UK to Introduce Chemical Castration for Sex Offenders Amid Prison Overcrowding Crisis

British Justice Secretary Shabana Mahmood speaks in the No. 9 Downing Street Media Briefing Room, in Westminster, London, May 14, 2025.

The British government has announced the rollout of medication to suppress the sex drive of sex offenders, as part of an extensive strategy to curb reoffending rates and address the growing pressure on the prison system, which is nearing full capacity.

Justice Secretary Shabana Mahmood confirmed on Thursday that the use of so-called "chemical castration" will be introduced in 20 prisons across two regions of England. She also stated that she is considering making the treatment mandatory in the future. The announcement followed the publication of an independent sentencing review led by former justice secretary David Gauke.

“Of course, it is vital that this approach is taken alongside psychological interventions that target other causes of offending, like asserting power and control,” Mahmood told Parliament. She emphasized that while chemical castration may not be suitable for all sex offenders — such as those whose crimes are driven by dominance rather than sexual compulsion — existing research indicates the treatment can lead to a 60% reduction in reoffending rates.

The treatment has previously been implemented on a voluntary basis in countries like Germany and Denmark and is mandatory for certain offenders in Poland.

The review also included broad recommendations to overhaul the prison system, which currently houses nearly 90,000 inmates — double the figure from 30 years ago — despite a drop in crime rates. The surge in prison population is attributed in part to harsher sentencing guidelines aimed at demonstrating a tough stance on crime.

Among the proposed reforms, the review suggested eliminating prison sentences under 12 months, except in cases involving domestic abuse. It also advocated for earlier prisoner release to manage overcrowding, more flexible sentencing options such as driving bans, and the immediate deportation of foreign nationals sentenced to three years or less.

To support these measures, Mahmood pledged £700 million ($930 million) annually for the probation service, allowing probation officers to dedicate more time to rehabilitation efforts. The review also recommended increased investment in electronic tagging for offenders serving sentences in the community.

Critics, including Conservative justice spokesman Robert Jenrick, expressed concerns that scrapping short-term sentences could amount to "decriminalizing" crimes such as burglary, theft, and assault. He also questioned the effectiveness of electronic monitoring, comparing it to "smoke alarms putting out bonfires."

In response, Mahmood defended the government’s approach, stating it was necessary to fix the neglected judicial system inherited from the previous Conservative administration. She also highlighted Labour’s commitment to expanding prison infrastructure, launching the largest expansion of the prison estate since the 19th century.

“If our prisons collapse, courts are forced to suspend trials,” Mahmood warned. “The police must halt their arrests, crime goes unpunished, criminals run amok and chaos reigns. We face the breakdown of law and order in this country.”